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chore: import upstream snapshot with attribution
2026-07-13 13:37:14 +08:00

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Python

# Copyright (c) 2024 PaddlePaddle Authors. All Rights Reserved.
# Copyright 2024 The Qwen team, Alibaba Group and The HuggingFace Inc. team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Tokenization classes for Qwen2."""
from __future__ import annotations
import json
import os
import unicodedata
from functools import lru_cache
from typing import Any, Dict, List, Optional, Tuple
import regex as re
from ...utils.log import logger
from .. import AddedToken, PretrainedTokenizer
VOCAB_FILES_NAMES = {
"vocab_file": "vocab.json",
"merges_file": "merges.txt",
}
__all__ = ["Qwen2Tokenizer"]
MAX_MODEL_INPUT_SIZES = {"__internal_testing__/tiny-random-qwen2": 32768}
PRETOKENIZE_REGEX = r"""(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+"""
@lru_cache()
def bytes_to_unicode():
"""
Returns list of utf-8 byte and a mapping to unicode strings. We specifically avoids mapping to whitespace/control
characters the bpe code barfs on.
The reversible bpe codes work on unicode strings. This means you need a large # of unicode characters in your vocab
if you want to avoid UNKs. When you're at something like a 10B token dataset you end up needing around 5K for
decent coverage. This is a significant percentage of your normal, say, 32K bpe vocab. To avoid that, we want lookup
tables between utf-8 bytes and unicode strings.
"""
bs = (
list(range(ord("!"), ord("~") + 1)) + list(range(ord("¡"), ord("¬") + 1)) + list(range(ord("®"), ord("ÿ") + 1))
)
cs = bs[:]
n = 0
for b in range(2**8):
if b not in bs:
bs.append(b)
cs.append(2**8 + n)
n += 1
cs = [chr(n) for n in cs]
return dict(zip(bs, cs))
def get_pairs(word):
"""
Return set of symbol pairs in a word.
Word is represented as tuple of symbols (symbols being variable-length strings).
"""
pairs = set()
prev_char = word[0]
for char in word[1:]:
pairs.add((prev_char, char))
prev_char = char
return pairs
class Qwen2Tokenizer(PretrainedTokenizer):
"""
Construct a Qwen2 tokenizer. Based on byte-level Byte-Pair-Encoding.
Same with GPT2Tokenizer, this tokenizer has been trained to treat spaces like parts of the tokens so a word will
be encoded differently whether it is at the beginning of the sentence (without space) or not:
```python
>>> from transformers import Qwen2Tokenizer
>>> tokenizer = Qwen2Tokenizer.from_pretrained("Qwen/Qwen-tokenizer")
>>> tokenizer("Hello world")["input_ids"]
[9707, 1879]
>>> tokenizer(" Hello world")["input_ids"]
[21927, 1879]
```
This is expected.
You should not use GPT2Tokenizer instead, because of the different pretokenization rules.
This tokenizer inherits from [`PreTrainedTokenizer`] which contains most of the main methods. Users should refer to
this superclass for more information regarding those methods.
Args:
vocab_file (`str`):
Path to the vocabulary file.
merges_file (`str`):
Path to the merges file.
errors (`str`, *optional*, defaults to `"replace"`):
Paradigm to follow when decoding bytes to UTF-8. See
[bytes.decode](https://docs.python.org/3/library/stdtypes.html#bytes.decode) for more information.
unk_token (`str`, *optional*, defaults to `"<|endoftext|>"`):
The unknown token. A token that is not in the vocabulary cannot be converted to an ID and is set to be this
token instead.
bos_token (`str`, *optional*):
The beginning of sequence token. Not applicable for this tokenizer.
eos_token (`str`, *optional*, defaults to `"<|endoftext|>"`):
The end of sequence token.
pad_token (`str`, *optional*, defaults to `"<|endoftext|>"`):
The token used for padding, for example when batching sequences of different lengths.
clean_up_tokenization_spaces (`bool`, *optional*, defaults to `False`):
Whether or not the model should cleanup the spaces that were added when splitting the input text during the
tokenization process. Not applicable to this tokenizer, since tokenization does not add spaces.
split_special_tokens (`bool`, *optional*, defaults to `False`):
Whether or not the special tokens should be split during the tokenization process. The default behavior is
to not split special tokens. This means that if `<|endoftext|>` is the `eos_token`, then `tokenizer.tokenize("<|endoftext|>") =
['<|endoftext|>`]. Otherwise, if `split_special_tokens=True`, then `tokenizer.tokenize("<|endoftext|>")` will be give `['<',
'|', 'endo', 'ft', 'ext', '|', '>']`. This argument is only supported for `slow` tokenizers for the moment.
"""
resource_files_names = VOCAB_FILES_NAMES
model_input_names = ["input_ids", "attention_mask", "attn_mask_startend_row_indices"]
max_model_input_sizes = MAX_MODEL_INPUT_SIZES
pretrained_resource_files_map = {
"vocab_file": {
"__internal_testing__/tiny-random-qwen2": "https://bj.bcebos.com/paddlenlp/models/community/qwen2/vocab.json",
},
}
def __init__(
self,
vocab_file,
merges_file,
errors="replace",
unk_token="<|endoftext|>",
bos_token=None,
eos_token="<|endoftext|>",
pad_token="<|endoftext|>",
clean_up_tokenization_spaces=False,
split_special_tokens=False,
**kwargs,
):
if unk_token is None:
logger.info("The `unk_token` parameter needs to be defined: we use `eos_token` by default.")
unk_token = eos_token
# Qwen vocab does not contain control tokens; added tokens need to be special
bos_token = (
AddedToken(bos_token, lstrip=False, rstrip=False, special=True, normalized=False)
if isinstance(bos_token, str)
else bos_token
)
eos_token = (
AddedToken(eos_token, lstrip=False, rstrip=False, special=True, normalized=False)
if isinstance(eos_token, str)
else eos_token
)
unk_token = (
AddedToken(unk_token, lstrip=False, rstrip=False, special=True, normalized=False)
if isinstance(unk_token, str)
else unk_token
)
pad_token = (
AddedToken(pad_token, lstrip=False, rstrip=False, special=True, normalized=False)
if isinstance(pad_token, str)
else pad_token
)
with open(vocab_file, encoding="utf-8") as vocab_handle:
self.encoder = json.load(vocab_handle)
self.decoder = {v: k for k, v in self.encoder.items()}
self.errors = errors # how to handle errors in decoding
self.byte_encoder = bytes_to_unicode()
self.byte_decoder = {v: k for k, v in self.byte_encoder.items()}
bpe_merges = []
with open(merges_file, encoding="utf-8") as merges_handle:
for i, line in enumerate(merges_handle):
line = line.strip()
if (i == 0 and line.startswith("#version:")) or not line:
continue
bpe_merges.append(tuple(line.split()))
self.bpe_ranks = dict(zip(bpe_merges, range(len(bpe_merges))))
# NOTE: the cache can grow without bound and will get really large for long running processes
# (esp. for texts of language that do not use space between word, e.g. Chinese); technically
# not a memory leak but appears as one.
# GPT2Tokenizer has the same problem, so let's be consistent.
self.cache = {}
self.pat = re.compile(PRETOKENIZE_REGEX)
if kwargs.get("add_prefix_space", False):
logger.warning_once(
f"{self.__class__.__name} does not support `add_prefix_space`, setting it to True has no effect."
)
super().__init__(
errors=errors,
bos_token=bos_token,
eos_token=eos_token,
pad_token=pad_token,
unk_token=unk_token,
clean_up_tokenization_spaces=clean_up_tokenization_spaces,
split_special_tokens=split_special_tokens,
**kwargs,
)
@property
def vocab_size(self) -> int:
return len(self.encoder)
def get_vocab(self):
return dict(self.encoder, **self.added_tokens_encoder)
def bpe(self, token):
if token in self.cache:
return self.cache[token]
word = tuple(token)
pairs = get_pairs(word)
if not pairs:
return token
while True:
bigram = min(pairs, key=lambda pair: self.bpe_ranks.get(pair, float("inf")))
if bigram not in self.bpe_ranks:
break
first, second = bigram
new_word = []
i = 0
while i < len(word):
try:
j = word.index(first, i)
except ValueError:
new_word.extend(word[i:])
break
else:
new_word.extend(word[i:j])
i = j
if word[i] == first and i < len(word) - 1 and word[i + 1] == second:
new_word.append(first + second)
i += 2
else:
new_word.append(word[i])
i += 1
new_word = tuple(new_word)
word = new_word
if len(word) == 1:
break
else:
pairs = get_pairs(word)
word = " ".join(word)
self.cache[token] = word
return word
def _tokenize(self, text):
"""Tokenize a string."""
bpe_tokens = []
for token in re.findall(self.pat, text):
token = "".join(
self.byte_encoder[b] for b in token.encode("utf-8")
) # Maps all our bytes to unicode strings, avoiding control tokens of the BPE (spaces in our case)
bpe_tokens.extend(bpe_token for bpe_token in self.bpe(token).split(" "))
return bpe_tokens
def _convert_token_to_id(self, token):
"""Converts a token (str) in an id using the vocab."""
return self.encoder.get(token, self.added_tokens_encoder.get(token, len(self.encoder)))
def _convert_id_to_token(self, index):
"""Converts an index (integer) in a token (str) using the vocab."""
return self.decoder.get(index, self.added_tokens_decoder.get(index, self.unk_token))
def convert_tokens_to_string(self, tokens):
"""Converts a sequence of tokens (string) in a single string."""
text = "".join(tokens)
text = bytearray([self.byte_decoder[c] for c in text]).decode("utf-8", errors=self.errors)
return text
def _decode(
self,
token_ids,
skip_special_tokens: bool = False,
clean_up_tokenization_spaces: Optional[bool] = False,
spaces_between_special_tokens: bool = False,
**kwargs,
) -> str:
# `spaces_between_special_tokens` defaults to True for _decode in slow tokenizers
# and cannot be configured elsewhere, but it should default to False for Qwen2Tokenizer
return super()._decode(
token_ids,
skip_special_tokens=skip_special_tokens,
clean_up_tokenization_spaces=clean_up_tokenization_spaces,
spaces_between_special_tokens=spaces_between_special_tokens,
**kwargs,
)
def save_vocabulary(self, save_directory: str, filename_prefix: Optional[str] = None) -> Tuple[str]:
if not os.path.isdir(save_directory):
logger.error(f"Vocabulary path ({save_directory}) should be a directory")
return
vocab_file = os.path.join(
save_directory, (filename_prefix + "-" if filename_prefix else "") + VOCAB_FILES_NAMES["vocab_file"]
)
merge_file = os.path.join(
save_directory, (filename_prefix + "-" if filename_prefix else "") + VOCAB_FILES_NAMES["merges_file"]
)
with open(vocab_file, "w", encoding="utf-8") as f:
f.write(json.dumps(self.encoder, indent=2, sort_keys=True, ensure_ascii=False) + "\n")
index = 0
with open(merge_file, "w", encoding="utf-8") as writer:
writer.write("#version: 0.2\n")
for bpe_tokens, token_index in sorted(self.bpe_ranks.items(), key=lambda kv: kv[1]):
if index != token_index:
logger.warning(
f"Saving vocabulary to {merge_file}: BPE merge indices are not consecutive."
" Please check that the tokenizer is not corrupted!"
)
index = token_index
writer.write(" ".join(bpe_tokens) + "\n")
index += 1
return vocab_file, merge_file
def prepare_for_tokenization(self, text, **kwargs):
text = unicodedata.normalize("NFC", text)
return (text, kwargs)
def _encode_chat_inputs(
self,
conversations: List[List[str, str]],
context_data: Dict[str, Any] = {},
system: str = None,
add_generation_prompt=True,
):
result = {}
# Some template do not support system msg, so we need to check it first.
if system:
try:
self.chat_template.render(messages={"role": "system", "content": system})
except Exception as e:
raise ValueError("System is not supported in this tokenizer.", e)
# convert list msg to role dict msg
conversation_dict = []
origin_msg = []
for round in conversations:
round_role = [
{"role": "user", "content": round[0]},
{"role": "assistant", "content": round[1]},
]
origin_msg.extend(round_role)
conversation_dict.append(round_role)
# Get system string in ChatTemplate
# ChatTemplate contains three parts: system, user, and assistant.
# However, the system string cannot be obtained directly with the chat_template.render() function.
# Thus, three steps are needed to extract the system string.
# Step 1: Obtain the combined system and user string in the first round.
# Step 2: Obtain the special system string.
# Step 3: Obtain the special combined system and user string in the first round.
# Then, user string = (special system and user string) - (special system string)
# And, system string = (initial system and user string) - (user string)
assert len(conversation_dict) > 0, "conversations is empty"
def replace_first_occurrence(original_string, to_find, to_replace):
index = original_string.find(to_find)
if index == -1: # to_find not found in original_string
return original_string
else:
return original_string[:index] + to_replace + original_string[index + len(to_find) :]
if system:
system_str = self.chat_template.render([system])
else:
# get system and user str
round0_str = self.chat_template.render(
messages=conversation_dict[0][:1], add_generation_prompt=False, **self.special_tokens_map
)
# get special system str
round0_only_system_str = self.chat_template.render(
messages=[{"role": "system", "content": ""}], add_generation_prompt=False, **self.special_tokens_map
)
# get special system and user str
round0_system_user_str = self.chat_template.render(
messages=[{"role": "system", "content": ""}] + conversation_dict[0][:1],
add_generation_prompt=False,
**self.special_tokens_map,
)
# get user str = {special system and user str} - {special system str}
user_str = replace_first_occurrence(round0_system_user_str, round0_only_system_str, "")
# get system str = { system and user str} - {user str}
system_str = round0_str.replace(user_str, "")
no_ans = []
ans = []
for conv in conversation_dict:
roundi = [system] + conv if system else conv
roundi_str = self.chat_template.render(
messages=roundi, add_generation_prompt=False, **self.special_tokens_map
)
roundi_no_ans = [system] + [conv[0]] if system else [conv[0]]
roundi_no_ans_str = self.chat_template.render(
messages=roundi_no_ans, add_generation_prompt=add_generation_prompt, **self.special_tokens_map
)
roundi_ans_str = roundi_str[len(roundi_no_ans_str) :]
ans.append(roundi_ans_str)
roundi_no_ans_no_system_str = replace_first_occurrence(roundi_no_ans_str, system_str, "")
assert (
roundi_no_ans_str == system_str + roundi_no_ans_no_system_str
), f"the src string contains system str: {system_str}"
no_ans.append(roundi_no_ans_no_system_str)
# the first round is special, we need to add system_str
no_ans[0] = system_str + no_ans[0]
conversation_ids = []
for i in range(len(no_ans)):
conversation_ids.append(
self.batch_encode(
[no_ans[i], ans[i]],
add_special_tokens=False,
padding=False,
)["input_ids"]
)
result["conversations"] = conversation_ids
return result